Influence of roofing materials and lead flashing on rainwater tank contamination by metals

Abstract

The quality of rainwater collected in polyvinyl chloride (PVC) tanks from six trial roofs (glazed tile, pre-painted steel and aluminium-zinc coated steel, each with and without uncoated lead flashing) was monitored for nine months. Samples of water and sediment were collected at three monthly intervals and analysed for concentrations of metals (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn), in order to determine the influence of roof materials and uncoated lead (Pb) flashing upon metal contamination within the tanks. Lead concentration in tank water exceeded Australian Drinking Water Guidelines for all roof types where there was lead flashing. Lead flashing also contributed to contamination of tank sediments. In all cases, pH was low which contributed to a large proportion of lead being in the dissolved form.

Keywords:

• Rainwater harvesting
• sediment quality
• heavy metals
• lead flashing
• lead contamination

Additional information

Notes on contributors

M I Magyar

Dr Mirela Magyar has more than 15 years’ experience in water and environmental management, and has worked in the water industry in Australia and Europe. Mirela received her PhD from Monash University and a Master of Science (Chemical Engineering) from The Polytechnic University of Timisoara, Romania. Her interests include the performance of water treatment technologies, and water quality aspects and potential risks associated with use of alternative water sources. Her PhD project “Investigating the factors that affect outlet water quality from residential rainwater tanks in Australia” also identified appropriate controls that mitigate the risks of reduced water quality from rainwater tanks.

A R Ladson

Dr Tony Ladson has more than 20 years’ experience in hydrology and river management, and has worked on projects throughout Australia and in the US and Taiwan. He has a PhD from the University of Melbourne, a Master of Science from the University of Minnesota and also studied at Uppsala University in Sweden. He retains associate status of both Monash University and the University of Melbourne. In 2000 he was awarded a Victorian Fellowship to undertake international research into adaptive management of environmental flows, and in 2005 received the GN Alexander Medal from Engineers Australia for work on evaluation of stream rehabilitation projects.

C Diaper

Dr Clare Diaper is a research scientist with over 15 years’ experience in the water industry in both Australia and Europe. Through her work at Cranfield University in the UK and CSIRO in Australia, Clare has collaborated with water companies, universities, Cooperative Research Centres and voluntary organisations developing ways to deliver alternative water services to industries, cities and towns. From rainwater collection to water recycling, Clare has explored human and environmental health aspects, treatment system performance and monitoring and stakeholder engagement of integrated water management options. Clare has also investigated how these factors contribute to the overall sustainability of these alternative options.

V G Mitchell

Dr Grace Mitchell is the Manager of the Water Accounting Section at the Bureau of Meteorology. Previous to this, she worked in the field of urban water research for over ten years, with CSIRO and Monash University. Grace received her BE (Civil, 1st) from The University of Canterbury, New Zealand, and her PhD from Monash University.